Arquivo Brasileiro de Medicina Veterinária e Zootecnia
On-line version ISSN 1678-4162
YOKOO, M.J. et al. Reproductive traits and their associations with other economically important traits in Nelore. Arq. Bras. Med. Vet. Zootec. [online]. 2012, vol.64, n.1, pp.91-100. ISSN 1678-4162. http://dx.doi.org/10.1590/S0102-09352012000100014.
Heritability (h2) and genetic correlations (rg) were estimated between reproductive traits such as age at first calving (AFC), first calving interval (FCI) and other economically relevant traits, i.e., weight (W) at year (Y) and at 18 months of age (S), scrotal circumference (SC), and hip height (HH) in Nelore cattle. The genetic parameters were estimated in a multiple-trait analysis, with animal models using the Bayesian inference by Gibbs Sampling algorithm. The genetic parameters estimated in this work suggest the existence of genetic variability for AFC (h2 = 0.26), where the selection for the reduction of Nelore females AFC should respond to mass selection, without causing genetic antagonism in the selection of W (rg = -0,22 (Y) and -0,44 (S)), and SC (rg = 0,02). The selection for the AFC in the long term could lead to an increase in the animal's frame, although this association is relatively low (-0.35). The posteriori heritability estimate for FCI was low, 0.11±0.03. The rg between FCI and the other traits studied indicate that selection for these growth traits will not affect the FCI.
Keywords : genetic correlation; heritability; hip height; variance components; sexual precocity.